Mill



AUS 1' 1939- R. s. BUTLER 2,168,089

MILL Original FIiled` Dec. 3l, 1934 Z I l E: E" 4A.. I nl i y l z3 '41. Exilim-HY- jg 3 I 74 291,516 175 J4 J/ Iizvez'o'r:

embodiment, the

Patented Aug. l, 1939 UNITED STATES PATENT OFFICE MILL Massachusetts Application December 31, 1934, Serial No. '159,909 Renewed April 26, 1939 12 Claims.

My invention relates to size-reducing mills, and particularly to mills which are especially adapted for the reduction of masses of rock, ore, retort residues, coal and other materials, from medium size, say several inches in maximum dimension, to a mixture of material ranging from pieces half an inch in maximum dimension down to a fine powder.

In general, my invention is intended to perform more simply, emciently and at less expense, the operations performed by all but the largest sizes of size-reducing mills of al1 present types.

An object of my invention is to provide an improved size-reducing mill. my invention is to provide an improved sizereducing mill requiring a minimum amount of power. A further object of my invention is to provide a size-reducing mill of extremely simple construction and having a very small number of moving parts. A further object of my invention is to provide an improved size-reducing mill of the impact type. Yet another object of my Invention is to provide an improved size-reducing mill in which a very large number of blows of very siibstantial force may be imparted to the material to be reduced in size in a short. period of time and in a machine of smaller dimensions than is possible with existing types. Still another object of my invention is to provide an improved size-reducing mill of a`type in which, when the feed is discontinued, the .power required will automatically be reduced to a minimum. Still another object of my invention is to provide an improved size-reducing apparatus in which the kinetic energy of cooperating moving parts may be availed of in effecting the sizereducing action. Other objects and advantages of the invention will hereinafter more fully appear.

In the accompanying drawing, in which in simplifled form one illustrative embodiment which my invention mayassume in practice, has been shown for purposes of illustration:

Fig. 1 is a view in approximately central longitudinal vertical section through the illustrative plane of the section through the driving means being parallel to but offset from that of the section through the mill proper.

Fig. 2 is a partial top plan view. f

Fig. 3 is a vertical transverse section. with parts shown in full, on a plane which corresponds to the line 3-3 of Fig. 1.

` It will be appreciated that` appropriate feeding devices, whether of the continuous yor inter- Another object of mittent type, and suitable devices for carrying away processed material, and desirably suitable devices for preventing loss of processed material in the form of dust, would be associated with my improved size-reducing mill in actual use, 5 but since such devices may assume various forms, and vary Widely in construction, I have not shown the same in connection with the illustrative embodiment of the invention, but have confined the disclosure to a simplified showing l0 of the size-reducing mill itself so that the essential features thereof may be the more readily appreciated. y

It will be noted that a base I, herein shown as having thereon integral opposite lateral supl5 port plates 2', reinforced by webs 3, provides a support for a, transverse shaft 'I'he latter is provided with suitable oscillating means, herein shown in the form of an end crank arm 5 whose crank pin 6 is connected byy a connecting rod 20 1 to a crank pin 8 suitably supported by webs 9 of a crank shaft I0. This crank shaft is shown as journaled in suitable cap bearings II upon slightly elevated portions I2, herein spaced from the main Vparts of the said frame members 2, 25 and-supports driving means and energy storing means, which may assume various forms, but which are herein shown as combined in a heavyrimmed, Wide-faced flywheel I3 which plays both the function of storing energy and that of a 30 driving pulley. The transverse shaft 4 is pivotally mounted in suitable bearings I5 supported herein between the caps I6 and the tops of the side members 2; and will be oscillated in the bearings described through an appropriate arc 35 (with the proportions shown, some 30) upon rotation of the crank shaft I0. Suspended for oscillation relative to the transverse shaft 4 by separable bearings I8, is a free-swinging chamber I9 having a portion 20 through which ma- 40 terial to be processed is adapted to be fed, and

a chamber 2I in which the size-reducing action may take place. The chamber 2| is herein shown as more or less circular in cross section, and

is curved, so that it follows throughout its length 45 substantially the arc of a circle struck on a radius of a length equal to the distance from the axis of the shaft 4 to a point midway between the top and bottom of a size-reducing member proper 30 hereinafter more fully described. The 50 chamber has aremovable wall 22 held in position by holding devices 23, and is preferably provided with a liner-24 of highly abrasion-re sisting material, a chrome alloy steel being a very satisfactory material. Suitable means' for 55 i proportion the passage from the chamber of processed material is provided, and herein this takes the form of a series of slots 25, appropriately screened, as at 26, by the liner 24 and extending throughout the greater portion oi! the length of the bottom wall of the chamber 2l. Between the opposite walls of the chamber member I8 there is mounted upon the shaft I, for oscillation` mill is to be used. Very hard rock may revao quire a solid, very heavy member 28, while on softer material' more crushing can be accomplished in a given time by use of a large head, which may, however, be made hollow because a reduced force of blow may be sumcient to shatter material of the less hardness involved. lll'he member 28 is preferably made, atleast in its portion 38, of chrome steel or some other alloy steel possessing hardness and the capacity to resist abrasion, and if desired may be heatv treated to provide greaterl hardness. Material chamber is determined A Fig. 2) between the portion of 'the member 28 may be fed to the vinterior of the member I8 through-a suitable chute 33 supported by plates 3|, which are cut away, as at 35, to permit access to the'bearings ,I5 and I8.

material which l can. enter the size-reducing by the distance A (see It will be observedjthat the'maximumsize of secured to the shaft. and the end wall `of the chute 33. The'dimension of thechamber 2I measured.k along an arc containing .the path of oscillation of a point midway between the top andbottom of the chamber, may advantageously be determined by the vfollowing considerations. The dimension of the chamber will vary with the arcuate-,length of the positively-moved size-reducing member'28. It will varywith the materialsize,v that iis to say, with thesize of the of themember 28. The

' largest unbroken masses of material which are to bejprocessed. l `It will vary with the overall stroke freely-pivoted casing I8 will-be understood, when the device is in operation, to move part of the time in' the same direction as, and with the member 28,. and at other times to move in an opposite sense to the member 28. When the casing is being positively moved bythe member 28 and in the same dlrection with the latter, it will be understoodk that it will be accelerated, but that under no circum stances will it very materially exceed the maximum velocity of the member 28, but it may be expected to attain approximately the velocity of that m'ember if properly proportioned. It will preferably be made of such length that the member 28, which will decelerate steadily after each attainment of its maximum velocity and then be positively reversed and build up a new and opposite velocity, may substantially attain the maximum value of this opposite velocity prior to the instant when the opposite sides of a mass of material of maximum size are subjected to a crushing action by an end wall of the casing and that end of the head 38 which is adjacent to said end wall.

'Ihe foregoing considerations render the'calculation of the chamber form theoretically'possible and permitithe construction of a casing and power driven size-reducing member whose proportions may be thereafter empirically brought to the most `satisfactory relations without difll- Obviously, the weight of this passes culty. A generally desirable dimension will be found to be not far from one and one-half times the stroke of a point midway between the top and bottom of the head portion 30 of the member 28, plus the arcuate length of the said head portion, plus one and one-half times the maximum dimension of the material to be processed. 'I'he width of the chamber 2| will preferably be determined with reasonable closeness by the lateral width ofthe head 30 of the member 28; and the vertical dimensions of the working head 38 of the member 28 and of the chamber 2l, of which the latter will naturally be slightly larger than the former, will be determined by the desired weight of the positively moved size-reducing member and by the initial size of the material. The greater the hardness, the more, theoretically, the desired Weight of the member 28 and the less spreading of the blow l(which is a function of the diameter of the striking end) is desirable.-

The mode of operation of the illustrative embodiment of the invention will be understood from what has been described. The crank shaft II) will be driven by the combined flywheel and pulley I3, and thereby the member 28 will be oscillated. Until material is fed into the hopper 33 there will be no movement, materially, of the casing I9, and very little power will be required because the energy imparted to the member 28 during certain portions of the revolution of the crank shaft I8 will be returned to the latter in large measure during other portions of the revolutions thereof. When material is fed into the casing it will be struck by the opposite ends of the head 30 and will build up motion of the casing member I8, and as the operation approaches the normal maximum size-reducing capacity of which the device is capable, it will be found that when the member 28 is in vertical position (i. e., in substantially mid-position) and travelingat approximately its maximum velocity, the casing will be traveling 'in the same direction with its end wall which is adjacent tothe leading end of the head 30, separated from the latter only by a pad of partially processed material, which may perhaps be one-half the thickness-of the largest single pieces which are admitted, or which may be smaller, or, if the rate of discharge through the openings 254 is restricted, might also possibly be larger. As the positively-driven member 28 beyond its vertical position, it will begin to decelerate, and the chamber will gain upon it, so tospeak, and the forward end of the chamber will draw ahead of head 30, and the freeswinging chamber will be approaching its own mid-stroke position when the motion of the power-driven crusher element reverses. Thereafter, the now oppositely moving power-driven member'28 and the so-to-speak rear (in terms of momentary travel) casing end wall, between which there will be a charge of unprocessed material, will rapidly approach each other, and immaterial by the opposltely moving bodies twice in each revolution of the crank shaft, and at the end of each individual size-reducing operation the motion of the casing will be reversed and it will travel back with the member 28 whileits velocity (and momentum) will again build up, but in an opposite direction; while a new quantity of material to be processed enters the end of the casing which will next serve as a locus of size-reducing action, when the power-driven member 28 reverses its direction of travel. It will be noted that` the relative movement between the member 28 and the ends of the casing provides an opening from top to bottom between said size-reducing member and casing equal at least to the full diameter of the maximum-size material which enters the mill.

From the foregoing description, it will be noted that a very simple an deifective size-reducing device has been provided. It will be evident that it may assume other forms and that a plurality of power-driven impact members may be located within the freely-swinging casing; that rock or other material of any hardness or friability may be broken by appropriate design of the mill; -that substantially all the power except for friction losses imparted to the apparatus is expended in the processing of the material to be reduced in size; that since kinetic energy varies as the square of the velocity, very powerful blows may be obtained with very simple apparatus; that mere castings can be used with a minimum of machine work; and that when a reduced quantity of end product is required, this may be produced without a great loss in efliciency of operation. While I have in this application specically described one form which my invention may assume in practice, it will be understood that this form is shown for purposes of illustration and that the inventionmay be modled and embodied in various other forms without departing from its` spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, in a size-reducing mill, a casing having Walls and mounted for relatively free movement in a predetermined path, means for supplying material to be processed to the interior thereof irrespective of motion thereof in said path and for discharging processed material automatically during motion thereof, a size-reducing element extending intoV said casing in spaced relation to the walls of the latter, and supporting and actuating means for said sizereducing element for supporting the .samefor movements which change the contour of the space between it and said casing and for moving the same positively back and forth along the same line within said casing and with its path so disposed and of such amplitude that said casing remains unaffected by such movement of said element when said casing is empty of material to be reduced in size but is set in motion upon feed thereinto of such material by forces imparted to the casing wall through the material.

2. In a size-reducing mill, a 'size-reducing couple including a size-reducing member supported for translatory movement in opposite directions, and along the same line in each direction, in a predetermined path, and a casing member providing a chamber into which said sizereducing member extends and Within which said size-reducing member may move in its predetermined path out of contact with the walls of said chamber, said casing having supporting means 'ing supporting means providing for the free movement thereof in a path similar to the path of movement of said size-reducing member, a source of oscillatory motion, and means for imparting from said source directly only to the ilrst mentioned member of said size-reducing couple alternate opposite movements in its predetermined path.

3. In a size-reducing mill, a size-reducing couple including a size-reducing member supported for movement in opposite directions in alternation along a predetermined arcuate path, and a casing member providing a chamber into which said size-reducing member extends and within which said size-reducing member may move in its predetermined'path out vof contact with the walls of said chamber, said casing having supporting means providing for the free movement thereof in a path similar to the path of movement of said size-reducing member, a source of oscillatory motion, and means for imparting from said source directly only to the first A mentioned member of said size-reducing couple alternate opposite movements in its predetermined path.

4. In a'size-reducing mill, a size-reducing member, means for'` positively moving the same alternately in opposite directions in a predetermined arcuate path about a pivot disposed above such path, a casing providing a chamber into which said size-reducing member extends and Within which said size-reducing member may move in its predetermined path out of contact with the walls of said chamber, said casing havmovement thereof in a path similar to the path of movement of said size-reducing member, means for feeding material into said chamber adjacent the axis of arcuate movement thereof, and means for discharging processed material through the bottom of said chamber.

5. In a size-reducing mill, a size-reducing member having -oppositely-facing, blow-striking ends, means for positively moving the same back and forth in a predetermind path to impart blowstriking movements thereto, and a cooperating chamber-forming member supported for movement in either direction from a central position and automatically returning to said central position whenever displaced therefrom, said chamber-forming member having a size-reducproviding for the free.

that the ends thereof lie outside the limits of movement of said size-reducing member when said chamberforming member is in its centralposition and of such cross section that the longitudinally extending bounding walls thereof are spaced from said size-'reducing member whereby the latter may swing within said chamber without contact with the ends or'walls thereof when said chamber is empty of material.

6. In a size-reducing mill, a size-reducing member, means for positively imparting thereto rapid successive translatory movements in opposite directions in a predetermined path, a cooperating chamber-forming member providing a chamber having at its opposite ends portions adapted tocoact in a hammering action with said size-reducing member, said chamber housing said size-reducing member, said chamber, in the direction of movement of said size-reducing member, being of a length greater than the sum of 75 the amplitude f the translatory movement of said size-reducing member in its predetermined path and the length along that path of said sizereducing member and of a cross section such that there is clearance between said size-reducing member and the longitudinally extending walls of said chamber whereby in the absence of material from said chamber said chamber-forming member derives no motion from said size-reducing member, and means for mounting said chamber-forming member for guided movement similar to the movements of said size-reducing member and for automatic return to a median position from which said chamber-forming member is movable only by forces transmitted thereto by said size-reducing member through material introduced into said chamber.

'1. In combination, in a size-reducing mill, a

casing, a hammer within said casing, means for supporting and actuating said hammer to impart thereto alternate opposite movements of predetermined length in a predetermined path, means for supporting said casing inert but guiding the same for movement as motion is derived from said hammer, said casing having a size-reducing chamber therein of a size to accommodate. the predetermined movements of said hammer without contact between hammer and casing but providing a clearance such that material to be reduced fed thereto will cause movement to be imparted to said casing by said hammer, means for feeding material into said casing at either side of said hammer, and means for discharging continuously, as it is sumciently fractured, the processed material..

8. In a size-reducing mill, a pivoted poweroscillated size-reducing member having associated means for effecting the oscillation thereof, a casing surrounding said member and when empty of material and in its median position providing clear space all around said size-reducing member whereby it then remains unaffected by the oscillation of said member, said casing freely pivotable about the axis of oscillation of said member, and means for feeding material into said casing at opposite sides of said member and discharging it when reduced beyond the end of said member.

9. In a size-reducing mill, a pivoted size-reducl ing member having a working, blow-striking end below its pivot, means for effecting directly power-oscillation of said member, a casing pivotable about an axis from which it depends, the casing axis alined with said pivot, and said casing having opposite ends with which the opposite faces of said size-reducing member may alternately coact in a size-reducing opration and having all its longitudinally extending walls out of contact with said size-reducing member.

10. In a size-reducing mill, a freely pivoted casing having walls forming a size-reducing chamber, and a positively moved size-reducing means suspended Within said casing out of contact with the walls thereof and movable relative to said casing to alter its distance from certain of said walls, but, when 4the casing is stationaryl and empty of material to be processed, without imparting motion thereto, and the spacing of said casing Walls and the movements of said size-reducing means predetermined so that said size-reducing means imparts movement to the casing upon feed of material to said casing.

11. In a size-reducing mill, a freely pivoted casing normally maintained in a median position when saidl mill is idle and to which median position it automatically tends to return when displaced, said casing having walls forming a sizereducing chamber, and a positively moved sizereducing means suspended within the chamber in said casing in spaced relation to all of the Walls of the latter and movable bodily relative to said casing to vary its distance from certain of the chamber walls, but, when the casing is stationary and empty of material to be processed, without imparting motion thereto, and imparting movement to the casing away from said median position upon feed of material to said casing.

12. In a size-reducing mill, a freely pivotedcasing guided for movement in a predetermined path and providing a size-reducing chamber elongated in the casing and having at its opposite ends walls for exerting a crushing action upon material in said chamber, a power-actuated, positively-oppositely-moved size-reducing member suspended in said casing for unobstructed movement therein and traversing an elongated path therein of less length than the length of said chamber and constituting a casing-moving element and providing oppositely facing, alternately acting, blowstriking ends vcooperating with the chamber end walls'in the crushing of material, said casing receiving from said size-reducing member, but only when there is at least a predetermined minimum .quantity of material in said chamber, alternately opposite movements each in the same direction as saidmember away from its median position direction of movement of said in its path, and returned to said median position only by energy stored as a result of its displacement therefrom.

ROBERT S. BUTLER. 

